(CNN) - With less than four days before the Indiana Senate primary, incumbent Sen. Dick Lugar and his challenger Richard Mourdock made their closing arguments in new television ads released Friday - the final spots of a long, often-times ugly nomination battle.

"America faces serious challenges, but Hoosiers' courage and determination are unbreakable. It's this spirit that guides me every day in the Senate," Lugar says in the ad, "Spirit."FULL POST

(CNN) - The U.S. Chamber of Commerce, a major conservative, pro-business group, is showing its support for Sen. Dick Lugar with hundreds of thousands of direct mail pieces, just days before the longtime senator faces his biggest primary challenge in 35 years.

In the flier, the group praises Lugar for supporting the Keystone pipeline, a proposal that Republicans argue would create thousands of private sector jobs but has faced heavy pushback from Democrats and the president over environmental concerns.FULL POST

(CNN) – Conservative crooner Pat Boone lent his voice and support to Sen. Richard Lugar of Indiana via a radio ad on Friday in hopes of helping the six-term incumbent beat back a challenge from the right.

The successful pop singer and ardent Republican described the longest serving Republican senator as a "true conservative" who shares Hoosier State voter's "Midwestern values."FULL POST

(CNN) - Republican Senate candidate Richard Mourdock's campaign released a new radio ad Monday, hammering six-term incumbent Sen. Dick Lugar of Indiana and adding to the thickening tension between the two candidates in the final two weeks of the primary race.

The 60-second spot directly takes on recent Lugar attacks ads that target Mourdock as a tax fraud, highlighting the ads as "misleading," "an exaggeration" and " straining the facts."FULL POST

“The truth can take a beating in campaign time, and this year it’s Dick Lugar on the receiving end,” Daniels says in the ad. “It’s funny in a way, these folks from elsewhere, here telling us who’s a real Hoosier.”FULL POST

(CNN) - It's been 12 years since Indiana Sen. Dick Lugar faced off in a campaign debate.

That streak ends Wednesday night when the most senior Republican member of the Senate shares the stage with his conservative GOP challenger, Indiana State Treasurer Richard Mourdock, at a debate in Indianapolis that will be televised statewide in Indiana.FULL POST

The group has endorsed Lugar's challenger, Indiana state treasurer Richard Mourdock, ahead of the May 8 GOP senate primary. The race against Mourdock has seen Lugar, a six-term veteran of the U.S. Senate, challenged by tea party groups and others who proclaim him to be too moderate.FULL POST